Attachment to be applied to a duplicating mill for duplicating conical shapes



June 10, 1958 v BRIDWELL 2,837,976

ATTACHMENT TO BE APPLIED TO A DUPLICATING MILL .FOR DUPLICATING CQNICAL SHAPES Filed March 1, 1955 4 Sheets-Sheet 1 2066/? 6? Brx'awe/L INVEN TOR.

June 10, 1958 R. A. BRIDWELL 2,837,976

ATTACHMENT To- APPLIED TO UPLICATING MILL FOR DU CATING CONI SHAPES Filed March 1. 1955 T 4 Sheets-Sheet 2 Q m N q- I. O m m APbbe/T 62 540206,

INVENTOR.

June 10, 1958 R. A. BRIDWELL 2,837,976

ATTACHMENT TO BE APPLIED TO A DUPLICATING MILL FOR DUPLICATING CONICAL SHAPES Filed March 1. 1955 4 Sheets-Sheet 3 @aben 1Q. Brida /6M,

I N V EN TOR.

g1 JJ WM a/em flirt/77% v June 10, 1958 R. A. BRIDWELL 2,837,976

. ATTACHMENT TO APPLIED TO A DUPLICATING MILL FOR DU CATING CJNICAL SHAPES Filed March 1, 1955 4 Sheets-Sheet 4 @oerf 6? Bflda/e/A IN VEN TOR.

Robert A. Bridwell, Lynvvoed, (Ialifi, assignor to Northrop Aircraft, lilo, Hawthorne, Califi, a corporation of California Application March 1, 1955, Serial No. 491,455 Claims. (CI. 90-42) This invention has to do with power tools and more particularly with an attachment to be applied to a duplicating mill.

Heretofore it has been generally necessary, in order to duplicate conical shapes through the medium of a duplicating mill, to use an actual, full scale model of the device to be duplicated. This use of an actual model was a restricting factor for the simple reason that for each conical shape having different dimensions another model had to be prepared in advance. This resulted in a great number of man hours being expended before production of the device could be obtained resulting in the cost of the finished product being raised.

Therefore, the principal object of this invention is to provide an attachment to be applied to a duplicating mill that is capable of duplicating the configuration of virtually any conicalshape.

Another object of this invention is to provide an attachment to be applied to a duplicating mill that is simple in construction, has few structural parts, and is economical to manufacture.

Figure 1 is a schematic, perspective view illustrating the attachment of this invention as it is positioned relative to one type of conventional duplicating mill.

Figure 2 is an enlarged, perspective view illustrating and having embodied therein the present invention.

Figure 3 is a cross-sectional view taken on line 3-3 in Figure 2 looking in the direction indicated.

Figure 4 is a cross-sectional view taken on line 4-4 of Figure 2 looking in the direction indicated and illustrating the stylus of the duplicating mill in the guide therefor.

Figure 5 is a cross-sectional view taken on line 55 of Figure 2 looking in the direction indicated and illustrating the micrometer turret assembly for the guide bar.

Figure 6 is a cross-section, end elevational view of the micrometer turret assembly taken on line 6-6 of Figure 2 looking in the direcn' on indicated.

Figure 7 is a perspective view of a conical configuration as prepared by the use of the attachment of this invention. H

Figure 8 is a cross-sectional view taken on line 88 of Figure 7 looking in the direction indicated.

Figure 9 is a schematic view illustrating the position of the guide bar as it rests on the most elevated portion of a template.

Figure 10 is a view similar to Figure 9 but illustrating the position of the guide bar on an arcuate and inclined portion of the template.

Figure 11 is a fragmentary, cross-sectional view taken on line 11- 11 of Figure 2 looking in the direction indicated.

Referring to the drawings for a more detailed description of the present invention, ltl designates a conventional multiple headed duplicating mill having an adjustable stylus head 12 thereon with a stylus l4 projecting therefrom into the groove 16 of an elongated guide bar 18 of an attachment, broadly designated 20, that is remov- 2,837,976 Patented June 10, 1958 ably applied to the bed of the mill It). The stylus head 12 has pressure sensitive structure therein that is actuated by the stylus 14 when the latter comes or is brought into contact with a material to exert a pressure. The pressure sensitive structure is interconnected to the motor of the duplicating mill 14 As a result of a signal being transmitted from the head 12 to the motor the bed of the mill is caused to alter its position either horizontally or vertically or both.

The attachment comprises a fiat, polygonal base plate 22 having parallel sides 21 and 25 and parallel sides 23 and 27. A pair of notches 24 are cut in each of the sides 23 and 27 which receive bolts, studs, clamps or other equally applicable structure, for removably attaching the plate 22 to the bed of the mill 1t Secured to the plate 22 by studs or bolts 26, and pro jecting from side 27 thereof, are a pair of spaced apart parallel bearing brackets 23, for supporting a rotatable elongated shaft 30. The shaft 30 extends beyond each of the brackets 28, lies parallel to side 27 and has secured to one end thereof a handle 32, and to the other end is secured a bevel gear 34.

Lying parallel to side 25' and overlying plate 22 is another elongated and rotatable shaft 36 supported by hearing brackets 38; the latter also being secured to plate 22 by belts or studs 29. Secured to one end of shaft 36 and meshing with bevel gear 34 is another bevel gear 42. Located on the shaft 36 in opposed relationship to bevel gear 42 is a bevel gear 44 that meshes with bevel gear 46 on rotatable and elongated Worm gear 48; the latter, like shafts 39 and 36, being supported by spaced apart bearing brackets 59. Brackets 5% are secured to plate 22 by belts or studs 52. The gear 43 lies midway between the sides 23 and 27, is parallel thereto, and overlies the plate 22. That end of the gear 43 in opposed relation to bevel gear is has threaded thereon, to retain the shaft in position, a bolt 54. Threaded onto the gear 48 is a follower block 56; the latter having an opening therein to receive a rotatable stub shaft 53. Welded or otherwise secured to the shaft 58 is a plate 60 having integral therewith a pair of spaced apart fingers 62. The shaft 58 is resiliently retained in block 56 by a snap ring 64.

Located on each side of the gear 48 and equally spaced therefrom, secured to the plate 22 by belts or studs 66, and having their faces 68 parallel to shaft 48, are L-shaped template or pattern brackets '7 ti.

Supported by plate 60, between fingers 62, is the stylus guide bar 18. One end of the guide bar 18 is pressed into or otherwise secured to a micrometer disc 72, of a turret-like body broadly designated 73, having indicia thereon. The micrometer disc is in turn secured to a plate 74, by a bolt 76. An arcuate notch 78 is constructed in plate 74 through which extends a threaded stud 80 for attaching a handle 82 to the disc 72. Integral with plate 74 and projecting therefrom toward shaft 48 are parallel, spaced apart arms 84; the arms also being parallel to guide bar 18. Arms 84 are pivotally attached, by pins 83, to the legs 85 and 87 of a U-shaped support 86. Extending through an opening, midway between the ends of the bight 88 of support 86, is a reduced end 90 of a pivot shaft 92. The shaft 92 is supported on a plate 94 and is retained in position in this plate by a disc 96 being superimposed and secured thereon and engaging an annular flange or shoulder 93. Additionally one end 100 of the shaft 92, in opposed relation to end 90, projects into an opening 102 in plate 22. That portion of the shaft 92 between ends 90 and 100 is received in openings in plate 94 and disc 96. Opening 102 is in linear alignment with the openings in the bight 88, plate 24 and disc 96. The plate 94 is secured to plate 22 by bolts or studs 104.

Projecting from the bight 88 midway between the ends thereof and toward handle 82, is a spring support 106 having a flat 108 therein to receive one end of a compression spring 118, the other end being received in a groove formed in plate 74.

Freely slidable on guide bar 18 is a pattern or template follower and stylus stop 112 having an irregular shaped notch 113 formed therein that engages a template 114. One edge 116 of the template 114 is arcuate in order that a conical shape may be defined for the duplicating mill 10.

The template 114 is illustrated as being secured by bolts or studs 118 to L-shaped template brackets 120; the latter being in turn secured to plate 22 by bolts or studs 122. It may be seen, by referring to Figures 1 and 2 of the drawings, that there are two pairs of brackets 120 secured to the plate 22 at an acute angle relative to worm gear 48.

Using the invention herein described results in obtaining structure having the configuration illustrated in Figures 7 and 8. In the form shown in Figure 7, the maximum thickness is along line AB and tapering uniformly to the tips CD and the sides, in this instance defined by the line AB; the latter being illustrated in Figure 8 of the drawings. It is of course necessary that a proper out be made on both sides of the plate 124. The structure as illustrated has a peripheral bead E thereon that will be removed after completion of all necessary operations of preparing the surface.

The operation of the invention is as follows: The plate 22 and all related structure is mounted on the vertically and horizontally movable bed of the duplicating mill 10 in the manner illustrated in Figure 1 of the drawings. The plate 22 is caused to move, along with the bed, to the left as the structure is viewed in the aforementioned figure. The movement of the bed is controlled by the stylus 14 engaging the walls 126 and 128 of the groove 16 in guide bar 18. For instance, as stated the plate 22 is caused to be moved to the left and as it does so, the stylus 14 strikes wall 126 and the plate 22 is caused to move up, freeing the stylus from contact with the aforementioned wall. Again the plate 22 moves left until stylus 14 again strikes wall 126.

Now assume that a template 114 is secured to template brackets 12% as shown in dotted or full lines or secured to template brackets 70 as illustrated in dotted lines. The template follower 112 is freely slidable on the guide bar 18 and the notch 113 thereof engages the edge 116 of template 114. The operator of the machine may 10- cate the guide bar anywhere along the edge 116 of the template by manipulating handle 32 resulting in rotation being imposed on the shaft 30 which is transmitted through the various bevel gears to worm gear 48. The rotation of worms gear 48 causes block 56 to move relative thereto and the latter is prevented from rotation due to the fingers 62 engaging guide bar 18. Therefore as the block 56 is moved along worm gear 48 so is the guide bar 18. By virtue of this structural arrangement the guide bar 18, as stated, may be located in any position along the template 114 and this position of the guide bar in turn controls the movement of the plate 22 relative to the stylus 14 and the duplicating mill 10.

However, attention is directed to the feature illustrated in Figures 9 and 10 of the drawings. The guide bar 18 in template follower 112 must be located on its exact center 128 relative to the template 114 and for the following reason. Assume the guide bar 18 and template follower 112 to be in the position illustrated in Figure 9 of the drawings. The exact center 128 rests on the edge 116 of template 114. If the guide bar 18 were moved to the inclined position illustrated in Figure 10 of the drawings without correcting the center 128 relative to edge 116, it would be displaced and an error in the depth of cut made on plate 124 would result. Therefore, in order to eliminate this error the guide bar .18 is adjusted by rotating handle 82 which is secured to the micrometer disc 72. The guide bar 18 is also secured to disc 72 and as a result as the handle is turned so is the guide bar. Due to this construction the guide bar 18 may be adjusted in such a manner as to always have the center 128 thereof resting on the edge 116 of the template 114.

The guide bar 18 being secured to turret body 73 is free to rotate about the reference point defined by shaft 92 and is free to pivot about pins 83 securing arms 84 to support 86. However, the guide bar 18 is urged into the template engaging positions by spring 110 exerting its force against plate 74.

It will be understood that one half of the conical structure is made by the use of the described arrangement and operation; the other half being made by the necessary rearrangement thereof. In other words, the template 114 is illustrated in solid lines as being secured to brackets 128. This arrangement will provide for a cut being made on each side of plate 124 and defined as triangle ABC. By shifting the template 114 to the dotted line position to that illustrated in full lines as well as the guide bar structure, the triangle ABD could be cut on both sides of plate 124.

While in order to comply with the statute, the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprise a preferred form of putting the invention into effect, and the invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims.

What is claimed is:

1. An attachment to be applied to a duplicating mill for duplicating conical shapes comprising a plate that is affixed to the horizontally and vertically movable bed of the duplicating mill; a pressure sensitive stylus on said duplicating mill; a vertically and horizontally rotatable guide bar on said plate that is engaged by the stylus of said duplicating mill; a template on said plate that is engaged by said guide bar; and structure on said plate engaged by said guide bar, for changing the position of said guide bar on said template.

2. An attachment to be applied to a duplicating mill for duplicating conical shapes comprising a plate that is afiixed to the horizontally and vertically movable bed of the duplicating mill; a pressure sensitive stylus onxsaid duplicating mill; a vertically and horizontally rotatable guide bar on said plate that is engaged by the stylus of said duplicating mill; a templateon said plate that is engaged by said guide bar; a stylus engaging stop on said guide bar that slides along said template when said structure is caused to alter the position of said guide bar.

3. An attachment to be applied to a duplicating mill for duplicating conical shapes comprising a plate that is aflixed to the horizontally and vertically movable bed of the duplicating mill; a pressure sensitive stylus on said duplicating mill; a vertically and horizontally rotatable guide bar on said plate that is engaged by the stylus of said duplicating mill; a template on said plate that is engaged by said guide bar; and micrometer structure connected to said guide bar for rotating the latter with respect to said template.

4. An attachment to be applied to a duplicating mill for duplicating conical shapes comprising a plate that is affixed to the horizontally and vertically movable bed of the duplicating mill; a pressure sensitive stylus on said duplicating mill; a vertically and horizontally rotatable guide bar on said plate that is engaged by the stylus of said duplicating mill; a template on said plate that is engaged by said guide bar; a stylus engaging stop on said guide bar that slides along said template when said structure is caused to alter the position of said guide bar; and micrometer structure connected to said guide bar for rotating the latter with respect to said template.

5. In a duplicating mill having a horizontally and vertinected to said guide bar for rotating the latter with recally movable bed thereon, a pressure sensitive stylus spect to said template. therein, an attachment to be applied to a duplicating mill for duplicating conical shapes comprising a plate that is e erences Cited in he file of this patent releasably attached to the bed of said mill; a universally 5 UNITED STATES PATENTS movable guide bar on said plate that is engaged by said stylus; a template on said plate that is engaged by said i f 'i 2 guide bar; a series of manually driven, gear connected 06 z e ep 1954 rods and worm having a bar engagingfollower on the 9 i 195 latter that is adapted to change the position of said guide 10 2702496 Davls et e 5 bar on said template; and micrometer structure con- 

